1-3/4 vs 1-7/8 longtubes for SC Hemi?

[Gamester]

Which size longtube headers, 1-3/4 or 1-7/8, would give more overall TQ/HP for a supercharged 5.7L Hemi?

 

[Paluby]

1-3/8"?

 

[Gamester]

1-3/8"?

Miss typed, fixed now

 

[shane1981]

I would say 1 7/8

 

[MSExpress]

as big as you can get!

 

[Wild one]

I might hate the way my JBA 1 7/8" fit,but they sure didn't hurt my trucks bottem end,i went from 2.06/07 60 fts to 1.98/99 60 fts with the only changes being the headers,and my truck is a 3.21 geared truck.

 

[Gamester]

Along with your guy's feedback and after reading this little experiment on a SC 6.2L Vette...

Study: 1 3/4" Vs 1 7/8" Header Swap on a SuperCharged C6 - SmokinVette.com Forums

...I've decided I am going to go with some 1-7/8 ARHs.

Thanks

 

[Paluby]

I'm sure you won't be disappointed.

 

[Tomater03]

1 7/8 have proven gains, but I hate to be the party pooper, but there is a large difference in a NA 5.7L and a SC 6.2 LS build. Your talking about moving quite a bit more air and fuel and about a 200 horsepower difference. So I would t look to deep into that post when comparing them to a ram

 

[Gamester]

1 7/8 have proven gains, but I hate to be the party pooper, but there is a large difference in a NA 5.7L and a SC 6.2 LS build. Your talking about moving quite a bit more air and fuel and about a 200 horsepower difference. So I would t look to deep into that post when comparing them to a ram

My 5.7 is SC, as per the title of the post, so they are similar and "apples to apples" comparable

 

[Tomater03]

Oh snap! My bad lol. I didn't see the SC part. 1 7/8th is fine for a supercharged setup. Over kill on a NA setup. My apologies on not reading the whole title

 

[Hemi450hp]

Gamester, are you trying to build a dyno queen or a truck that actually performs on the street/track? Supercharged or not, if you are making 470hp and cant spin a tire off the line, then the last thing you need is a large primary header that is not going to show its potential until higher in the rpm range.

Yes, there are trucks running 1 7/8" headers and run very well, but these guys are at a much lower elevation and are racing their trucks...they had no problem breaking the rear tires loose even when they were bone stock. Unless you are building a dyno queen, I still feel like you are making the wrong choice on these. Doesnt matter if a motor is supercharged or not, the larger the primary is, the higher in the rpm band the power is going to come on. At your elevation, you need low rpm tq, not high rpm hp.

 

[Gamester]

Gamester, are you trying to build a dyno queen or a truck that actually performs on the street/track? Supercharged or not, if you are making 470hp and cant spin a tire off the line, then the last thing you need is a large primary header that is not going to show its potential until higher in the rpm range.

Yes, there are trucks running 1 7/8" headers and run very well, but these guys are at a much lower elevation and are racing their trucks...they had no problem breaking the rear tires loose even when they were bone stock. Unless you are building a dyno queen, I still feel like you are making the wrong choice on these. Doesnt matter if a motor is supercharged or not, the larger the primary is, the higher in the rpm band the power is going to come on. At your elevation, you need low rpm tq, not high rpm hp.

Hmm, dyno queen huh? So, you are saying that the tool that performance enthusiasts have been using to measure power output for decades has no "real world" correlation? Sorry, but that doesn't make sense to me friend.

A dyno just measures the real power output that is put to the ground. I have shown you a couple of examples of dyno charts that prove that 1-7/8 primary headers do in fact produce more low RPM torque and HP than 1-3/4.

Therefore, 1-7/8 headers would be a more logical purchase for low-end as well as overall gains. Not sure how you can dispute against an actual measurable difference like that...

 

[Hemi450hp]

Hmm, dyno queen huh? So, you are saying that the tool that performance enthusiasts have been using to measure power output for decades has no "real world" correlation? Sorry, but that doesn't make sense to me friend.

A dyno just measures the real power output that is put to the ground. I have shown you a couple of examples of dyno charts that prove that 1-7/8 primary headers do in fact produce more low RPM torque and HP than 1-3/4.

Therefore, 1-7/8 headers would be a more logical purchase for low-end as well as overall gains. Not sure how you can dispute against an actual measurable difference like that...

Because as I said when you first posted those tests, they are testing the difference on 600hp motors, not a stock 5.7 Ram with a base model procharger. The more power the motor makes, the more it will benefit from a larger size primary. At your current power level and elevation, you need all the help you can get when it comes to tq in the lower rpm band.

The dyno queen comment wasnt meant to be me talking down on you or your truck. There are numerous cars/trucks that put up big dyno numbers, but dont run worth a darn on the street or the track. Building a performance trucks is about being able to use all the power your motor is putting out. Part of doing this is making sure the mods you install give you power in the rpm range where you need it the most.

Its your truck though, so at the end of the day, do whatever you want to do. I'm trying to help you based on the 13 years of experience I have in testing numerous hemi trucks with just about every part you could possibly put on them. I've raced them, I've dynod them, I've driven them on the street, used them offroad, towed with them, and taken them on 2000-3000 mile roadtrips. Bigger primaries have always shown less tq in the lower rpms on these trucks.

 

[Gamester]

This post was comparing to the linked dyno test on a SC 6.2 Vette around the same power level, not that BB motor from the other post, so you may want to take a read through that; but I know what you are getting at.

Still though, I'm more inclined to believe a dyno than someone's opinion; it's just the way I'm wired being the technical guy I am. I didn't take offense to the dyno queen comment, I just find it odd that you don't consider dyno numbers applicable.

If you do have any dyno or 0-60 times or some kind of numbers on these trucks in particular comparing the two primary sizes performances, I would be interesting in seeing those however.

I'm thinking that after adding any longtubes along with the water/methanol injection system and that will allow a smaller pulley/more boost on the SC that it will greatly help my low RPM TQ. Guess we shall see.

Thanks

 

[Paluby]

You're comparing your setup to a super charged 6.2 Vette on the thought process it's putting out the same amount of power??

 

[Gamester]

Not exactly the same obviously, but same principle as well as comparable engine size and power levels. In case you guys missed the link I posted earlier, read through this...

Study: 1 3/4" Vs 1 7/8" Header Swap on a SuperCharged C6 - SmokinVette.com Forums

 

[Paluby]

Yeah I read it. He's putting out more than 100hp over you. I feel like that's not comparable. And the engine sizes differ by 30 cubic inches. The Hellcat is a 6.2L SC engine too but that's obviously different again from both Ram and Vette.

I'm just saying its apples to oranges.

 

[Hemi450hp]

This post was comparing to an SC 6.2 Vette around the same power level, not that BB motor from the other post, so you may want to take a read through that; but I know what you are getting at.

Still though, I'm more inclined to believe a dyno than someone's opinion; it's just the way I'm wired being the technical guy I am. I didn't take offense to the dyno queen comment, I just find it odd that you don't consider dyno numbers applicable.

If you do have any dyno or 0-60 times or some kind of numbers on these trucks in particular comparing the two primary sizes performances, I would be interesting in seeing those however.

Thanks

The Supercharged Vette still made 600hp, just like the big block in your first article though. If you are looking for a graph to compare to, then try to find one on a motor that is only making 450hp and see what the differences are.

These trucks are very tough to dyno, so you arent going to find many dyno graphs out there. You say yours made 470hp with just a base procharger kit at 5000' elevation, yet I have seen about 10 dynos with the same kit that only made 400-420hp at sea level...a few of those guys even had headers and a few other supporting mods. This doesnt mean that your graph is wrong, but it simply shows that dyno's are too inconsistent on these trucks to use as any form of comparison.

0-60 times on tuners are also very inconsistent because people do not correct their speedometer based on tire size, or they dont run on flat ground. Ive seen numerous high 13-low 14 second trucks claim 0-60 times in the mid-high 4 second range which we all know is nowhere close to being accurate.

My 03 Hemi with full bolt ons, ported heads, cam, and 3200 stall tq converter went almost a full tenth slower in the 60' when I went from a 1 5/8" primary header to a 1 3/4" header. Kyle (tomater03) above you has 1 of the fastest N/A 3rd gen 4dr trucks and still runs a 1 5/8" header on his truck as well cutting high 1.6 60' times, and he is not far from the power level you are at. The best 60' anyone has cut in a N/A 8sp without a tq converter is a 1.77 (he is also running 1 3/4" ARH headers.

Your elevation also comes into effect. Even at 5000', you should be blowing the tires off at your power level. I would be curious to see your dyno sheet to see what rpm the tq comes in at.

 

[shane1981]

I have all the common mods i guess you could say and 1 7/8 headers 8 speed 3.92 and my truck has blown the tires off since i bought it and no noticable low end loss with the headers.There is so much conflicting info and lies online if you read alot like i do that you just have to make your own decision sometimes.its just hard for me to believe that a sc that is supposed to add 150 hp to a bone stock 5.7 wont just melt the tires at any elevation with any header size. mine will without a sc and i live in memphis tn where its 97 with 105 or higher index most days during summer and i can turn the air on and sit back and leave 70 ft black marks whenever i want. That being said take the same exact vehicle and line them up and they will be different .ive done. it i guess they respond different to different things.